U.S. patent number 4,497,387 [Application Number 06/413,750] was granted by the patent office on 1985-02-05 for transformer with smooth-walled tank.
This patent grant is currently assigned to Transformatoren Union Aktiengesellschaft. Invention is credited to Erich Reiplinger.
United States Patent |
4,497,387 |
Reiplinger |
February 5, 1985 |
Transformer with smooth-walled tank
Abstract
Transformer having an active part thereof disposed in an
oil-filled, smooth-walled tank having side walls braced by ribs
secured by welding and subdivided into wall-high panels, the
panels, respectively, including a sheetmetal wall having a
resonance frequency f.sub.o smaller according to the function
f.sub.o =(S.multidot.k.sub.f)/B.sup.2 then twice line frequency,
wherein S is the thickness of the sheetmetal in cm, B the net panel
width in cm, and k.sub.f a constant having an absolute magnitude
which depends upon the length-to-width ratio of the panel, upon the
modulus of elasticity, upon the transverse contraction and upon the
specific gravity of the material used therefor.
Inventors: |
Reiplinger; Erich (Nuremberg,
DE) |
Assignee: |
Transformatoren Union
Aktiengesellschaft (Stuttgart, DE)
|
Family
ID: |
6141070 |
Appl.
No.: |
06/413,750 |
Filed: |
September 1, 1982 |
Foreign Application Priority Data
Current U.S.
Class: |
181/202; 336/100;
336/90 |
Current CPC
Class: |
H01F
27/33 (20130101); H01F 27/02 (20130101) |
Current International
Class: |
H01F
27/02 (20060101); H01F 27/33 (20060101); H02K
005/24 () |
Field of
Search: |
;181/200,202,210,284
;336/100,90,98 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Fuller; Benjamin R.
Attorney, Agent or Firm: Lerner; Herbert L. Greenberg;
Laurence A.
Claims
I claim:
1. Transformer having an active part thereof disposed in an
oil-filled, smooth-walled tank having side walls braced by ribs
secured by welding and subdivided into wall-high panels, the
panels, respectively, comprising a sheetmetal wall having a
resonance frequency f.sub.o smaller according to the function
f.sub.o =(S.multidot.k.sub.f)/B.sup.2 than twice the main electric
power line frequency, wherein S is the thickness of the sheetmetal
in cm, B the net panel width in cm, and k.sub.f a constant having
an absolute magnitude which depends upon the length-to-width ratio
of the panel, upon the modulus of elasticity, upon the transverse
contraction and upon the specific gravity of the material used
therefor.
2. Transformer tank according to claim 1 wherein said panels have a
minimum width of 50 cm.
3. Transformer tank according to claim 1 wherein sheetmetal having
a thickness of at least 1.2 cm forms the side walls, respectively,
in the region of the wall-high panels.
4. Transformer tank according to claim 1 wherein the ribs secured
by welding are radiators, and the width of the wall-high panels is
equal to twice the width of the radiators located on the side
walls.
5. Transformer tank according to claim 1 wherein the side walls are
assembled of panel-wide elements having vertical edges extending
outwardly at an angle therefrom for forming the ribs.
6. Transformer tank according to claim 1 wherein the side walls are
formed of adjacent panel-wide elements having ribs mutually forming
a profile of V-shaped cross section.
Description
SPECIFICATION
The invention relates to transformers and especially to such
transformers having an active part in an oil-filled smooth-walled
tank, the side walls of which are subdivided into wall-high panels
and are braced by ribs welded thereon.
Such smooth-walled tanks are generally used in large transformers.
To cool the coolant in these transformers, radiators are provided
either on the outer sides and/or end faces of the transformer tank,
or a cooling device which is integrated into a special structural
unti is used for this purpose.
Regardless of the type of cooling, the tanks for these large
transformers are designed from the viewpoint of strength and
ruggedness, however, for reasons of economy and for lowering the
shipping weight, minimization of the wall thickness of the metal
plates or sheets used is striven for. For this purpose, a great
number of ribs for stiffening the relatively large-area side walls
of the transformer tank is provided.
A consequent disadvantage is that, due to the desired light-weight
construction, the side walls of the tank have relatively high
resonance frequencies and, furthermore, vibrations occurring in the
tank side walls are damped only very slightly even for large
amplitudes. Because of this, transformers with tanks constructed in
this manner may act as noise radiators relatively often and,
moreover, with somewhat unexpectedly high noise levels.
It is accordingly an object of the invention to provide a
transformer with a smooth-walled tank which has an economical
construction ensuring that resonance vibrations of the tank side
walls with the transformer core are avoided and that, in addition,
the vibrations generated by the transformer core are radiated via
the side walls of the tank only after having been damped.
With the foregoing and other objects in view, there is provided in
accordance with the invention, a transformer having an active part
thereof disposed in an oil-filled, smooth-walled tank having side
walls braced by bars or ribs secured by welding and subdivided into
wall-high panels, the panels, respectively, comprising a sheetmetal
wall having a resonance frequency f.sub.o smaller, according to the
function
than twice the line frequency, wherein S is the thickness of the
sheetmetal in cm, B the net panel width in cm, and k.sub.f a
constant having an absolute magnitude which depends upon the
length-to-width ration of the panel, upon the modulus of
elasticity, upon the transverse contraction and upon the specific
gravity of the material used therefor.
In accordance with other advantageous features of the invention,
the panels have a minimum width of 50 cm, and the sheetmetal having
a thickness of at least 1.2 cm forms the side walls, respectively,
of the tank at least in the region of wall-high panels.
In accordance with further features of the invention, the width of
the wall-high panels is equal to twice the width of radiators
arranged on the side walls, and the side walls are assembled of
panel-wide elements having vertical edges which are engled-off
outwardly for forming the bars or ribs, the bars or ribs of
mutually adjacent panel-wide elements forming a profile of V-shaped
cross sections.
The inventive construction of tank side walls for transformer tanks
is very advantageous because it leads, in the end result, to a
reduction in the number of bars or ribs required for stiffening by
using heavier wall thicknesses and thereby permits, practically
without additional cost, the construction of transformers, having a
noise radiation which is lower than for transformers of standard
construction.
Other features which are considered as characteristic for the
invention are set forth in the appended claims.
Although the invention is illustrated and described herein as
embodied in a transformer with smooth-walled tank, it is
nevertheless not intended to be limited to the details shown, since
various modifications and structural changes may be made therein
without departing from the spirit of the invention and within the
scope and range of equivalents of the claims.
The construction and method of operation of the invention, however,
together with additional objects and advantages thereof will be
best understood from the following description of specific
embodiments when read in connection with the accompanying drawings,
in which:
FIG. 1 is a perspective view of a transformer tank with ribs welded
to the side walls, in accordance with one embodiment of the
invention; and
FIG. 2 is a fragmentary cross-sectional view of a side wall of
another embodiment of the transformer tank, assembled of wall-high
elements.
Referring now to the drawings and first, particularly, to FIG. 1
thereof, there is shown, in a prismatic housing with side or edge
lengths of several meters, the active parts of a transformer
arranged in an otherwise non-illustrated manner. The prismatic
housing is closed off laterally by side walls 1 and end walls 2.
The lower edges of the side walls 1 and of end walls 2 are jointed
in an oil-tight manner to an otherwise non-illustrated bottom
plate. At the upper edge of the side walls 1 and the end walls 2, a
flange 3 is provided on which a cover 4 is fastened, also
oil-tightly, yet removably.
On the outside of the side walls 1 and the end walls 2, ribs or
bars 5 for stiffening the walls 1 and 2 are welded-on by the end
faces or edges thereof. The side walls 1 as well as the end walls 2
are divided by the ribs 5 into individual panels from the
standpoint of vibration technology. Due to a given overdesign or
superdimensioning of the sheetmetal thickness in the side walls 1
and the end wall 2, the number of the ribs 5 is relatively small
and, simultaneously, the resonance frequency of the sheetmetal wall
in the individual panels is lower than twice the line
frequency.
FIG. 2 is a fragmentary cross-sectional view of a side wall 1 or
end wall 2 assembled from panel-wide elements 6. The vertical edges
of these panel-wide elements 6 are angled-off about a vertical line
or inclined at an angle less than 90.degree.. The angled-off or
inclined edges of mutually adjacent elements 6 therefore form a rib
of V-shaped cross section, respectively, having an outlying contact
line which is closed-off by a welded seam 7. The construction of
the side walls 1 and the end walls 2 out of the elements 6 permits,
due to the standardization thereof, a design of the transformer
tanks in accordance with the building-block principle and
contributes to a more economical production due to a possible
reduction of stock-keeping or storage of sheetmetal.
The foregoing is a description corresponding to German Application
No. P 31 35 420.3, dated Sept. 7, 1981, the International priority
of which is being claimed for the instant application, and which is
hereby made part of this application. Any discrepancies between the
foregoing specification and the aforementioned corresponding German
application are to be resolved in favor of the latter.
* * * * *